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—— Overview
As we all know, there are many ECU (Electronic Control Units) in a car. They communicate with each other through CAN, LIN, Gateway, etc., and control different actuators separately or together. Therefore, Calibration Engineers need to measure and calibrate the parameters of different ECU. Especially at present, with the increasingly complex vehicle functions, few OEMs choose to complete the software design and development of all ECU in the car independently, but choose to cooperate with multiple Tier1. Therefore, a unified measurement and calibration protocol is particularly important.
In the 1990s, an association for standardization of automation and measuring systems (ASAM) was established by European automotive companies such as Audi, BMW, Mercedes- Benz and Volkswagen. It is a standard association in the automotive industry, which is committed to the fields of data model, interface and language specification. At first, CCP (CAN Calibration Protocol) was released by the association. It is a kind of ECU calibration protocol based on CAN bus. Even now, there are still many European and American car manufacturers still using it.
CCP protocol limits its scope of use to CAN bus. However, in addition to CAN communication, there are also communication modes such as LIN, USB, FlexRay, etc. So, ASAM later released XCP (Universal Measurement and Calibration Protocol) to support the calibration and measurement of other communication methods.
• XCP on CAN
• XCP on Ethernet/TCP_IP&UDP_IP
• XCP on FlexRay
• XCP on SxI/SCI&SPI
• XCP on USB
—— Main Function
In the development and test of control system, ECU needs to go through the process of matching and calibration, so as to determine its operation parameters and control parameters. Sometimes, in order to realize the precise control and parameter matching modification of ECU, it is necessary to calibrate the ECU accurately and optimize the control parameters. The calibration and measurement of ECU can be realized quickly and effectively by using CCP / XCP.
The main functions are as follows：
• Upload ECU data and calibrate the data of ECU internal variables in real time
• Download ECU data and calibrate the data of ECU internal variables in real time
• Flashing Online to refresh the program and data inside ECU
• Handling multiple ECU systems at the same time
—— Mode Of Working
The principle of measurement and calibration of CCP/XCP is similar.
1. Adopt one-master and multiple-slave communication mode to realize that a single master can communicate with multiple slaves at the same time;
2. There are two ways to interact between the master and the slave: Polling mode and DAQ (Data Acquisition Command) mode;
3. When the master and the slave interact, combine the A2L file to achieve real-time calibration and measurement of the slave (ECU).
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